Now, as the NYT reports, it's not likely lifeguards will see the 1075 on the side of the pool:

But the operating plan also lays out a proposal to prevent Lake Mead from dropping below the trigger point. It allows water managers to send 40 percent more water than usual downstream to Lake Mead from Lake Powell in Utah, the river’s other big reservoir, which now contains about 50 percent more water than Lake Mead.

In that case, the shortage declaration would be avoided and Lake Mead’s levels restored to 1,100 feet or so.

Lake Powell, fed by rain and snowmelt that create the Colorado and tributaries, has risen more than 60 feet from a 2004 low because the upper basin states, Colorado, New Mexico, Wyoming and Utah, do not use their full allocations. The upper basin provides a minimum annual flow of 8.23 million acre feet to Arizona, Nevada and California. (An acre-foot of water is generally considered the amount two families of four use annually.)

In its August report the Bureau of Reclamation said the extra replenishment from Lake Powell was the likeliest outcome. Nonetheless, said Terry Fulp, the bureau’s deputy regional director for the Lower Colorado Region, it is the first time ever that the bureau has judged a critical shortage to be remotely possible in the near future.

However, with this news, I learned from the Review-Journal that what happens when the levels get down to 1075 feet isn't just that the feds declare drought:

Two things will happen at elevation 1,075: The federal government will declare the first-ever shortage on the river, and the Southern Nevada Water Authority board will vote on whether to build a controversial pipeline to tap groundwater across eastern Nevada.

Mulroy said the multibillion-dollar pipeline project would serve as a backup supply for the community, separate from the Colorado River.

The vote on whether to build it will come down to a simple choice, she said: "How much risk do you want to put yourselves in? What's your carrying capacity for risk?"

As for its intake pipes at Lake Mead, the authority is rushing to complete a third straw, at a cost of about $700 million, that will draw water from deeper in the reservoir.

Leaving aside the question of the groundwater, what a great question General Manager Pat Mulroy asks. Though I suspect if more people knew their carrying capacity for risk, their tolerance for it, well: we'd have fewer guys jumping motorcycles over burning cars. Cats would never break their legs. And casinos would shut down.

[UPDATE:Barry Nelson of the NRDC blogs about this too today, though he gets all poetic on the Colorado River's history:]

Three quarters of a century ago, the Colorado River was a nearly untouched river system. Remember, Hoover Dam was built just 70 years after John Wesley Powell first ran the wild rapids of the Grand Canyon. The dam represented new technology to tame the American frontier – providing abundant power and water. Today, however, signals the end of the hydraulic frontier. Welcome to the age of water efficiency.

So what do we need to do differently to meet our needs in the future? Here’s NRDC’s 2007 report, In Hot Water, with our suggestions.

Previously in Pacific Swell

KPCC's Molly Peterson on a Gilligan's Island style tour of environmental stories in and affecting Southern California. Named for the Yvor Winters poem: "The slow Pacific swell stirs on the sand/Sleeping to sink away, withdrawing land..."
Follow the blog at @PacificSwell and Molly at @KPCCmolly.